(Not Applicable)
The present invention relates generally to a method and apparatus for grading, and more particularly to a method and apparatus for grading surfaces of roads, including gravel roads and unmade roads.
It is well known for road working equipment, such as road graders, to have a single large blade which is supported between front and rear wheels to effect grading of roads. The known equipment is typically very large to provide sufficient force to support the blade when cutting or shifting substantially embedded rocks or substantial quantities of earth during a grading operation. The large equipment is generally expensive to manufacture and, thus purchase. Moreover, in order to not unduly damage the blade or other components of the equipment, the grading speed of such equipment is usually kept to a very slow speed, such as approximately 3-5 miles per hour (mph). Therefore a need exists for a road grader which can operate at speeds which are higher than typical road grading speeds, and which is not unduly damaged when the grader blade strikes an object.
The present invention provides a grader including a frame supported above a surface. At least one blade is pivotally fixed to the frame, and is positionable to engage the surface. A first biasing mechanism biases the blade toward a forward position. At least one leveling board is pivotally fixed to the frame, and is positionable to engage the surface rearwardly of the blade. A second biasing mechanism biases the leveling board toward a forward position. A packing mechanism is fixed rearwardly of the leveling board, and is positionable to engage the surface.
Another aspect of the present invention is a method of grading a surface of a road including reclaiming the road surface with at least one blade in a single pass, smoothing the reclaimed surface with at least one leveling board in the same pass as reclaiming the road surface, and packing the smoothed, reclaimed road surface in the same pass as smoothing the reclaimed surface.
A general objective of the present invention is to provide a grader which can grade a road by cutting, smoothing, and packing a road in a single pass. This objective is accomplished by providing a grader with a cutting blade, a leveling board, and a packing mechanism which operate as the grader travels along the road being reclaimed.
Another objective of the present invention is to provide a grader which can grade a road at a high speed. This objective is accomplished by providing a grader which can operate at speeds which are greater than conventional grading speeds. Preferably, the grader operates at a speed of at least 12 mph. Most preferably, the grader operates at speeds of at least 8 mph.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention.